Use neoprene front and rear seals for your Buick. Rear seal is Fel-Pro #BS40012 (Cadillac, must be slightly trimmed to fit), front seal is Federal-Mogul #470543. They can also be ordered from Torque Tech, TA Performance or Postons, all are listed on our vendors page. You can also use National Oil Seals, front 450446 and rear 5068.